DO_rare_slim NCIthesaurus has phenotype existence starts during adolescence-adult electroclinical syndrome juvenile myoclonic epilepsy SNOMEDCT_US_2025_09_01:6204001 disease_ontology GARD:6808 UMLS_CUI:C0270853 ORDO:307 MIM:254770 MESH:D020190 NCI:C84796 ORDO:862 DOID:4890 DOID:0050326 A adolescence-adult electroclinical syndrome that is characterized by brief, involuntary twitching of a muscle or a group of muscles (myoclonus) early in the morning with onset between 12 and 18 years. Janz syndrome Xref MGI. OMIM mapping confirmed by DO. [SN]. Myoclonus Young adult onset